If someone asked you if you could walk in a straight line blind-folded the obvious answer would be yes, wouldn’t it? Well, if you said yes than you’re in for a surprise. It is actually impossible for us to stay on a straight path while blind-folded. Jan Souman, a German scientist, conducted an experiment to see if someone could walk in a straight line while blind-folded. He found that when the participant had no visual landmarks to work off of they ended up walking in circles, even though they thought that they were staying on a straight path.
But what exactly is a straight line? Well, according to the free dictionary, “a line…traveling in a constant direction” or” a line of zero curvature.” In other words, having zero deviation throughout the entirety of the trip. In Jan Souman’s large scale experiment, where people were told to walk for up to an hour in a wide open area, a straight line meant not going in circles and staying in relatively one direction. However, in my much smaller scale experiments, where the participants will walk across a gym or small park area, a straight line will be the shortest distance between two points. In other words, if the participant deviates at all from the designated start point to the designated end point it will not be considered a straight line.
In my experiment I will be measuring how far the participant deviates from their path. They will have a very specific end point and in order to hit it they will have to remain on a near perfectly straight path. After each trial it will be measured, in feet, how far they deviated from a straight line.
So far I have talked a lot about walking in a straight line, but what exactly is walking? According to the free dictionary it is “To move over a surface by taking steps with the feet at a pace slower than a run.” Walking is a type of controlled falling where you let your body fall but catch yourself with your leading leg. It can also be described as an “inverted pendulum” where we see the center of mass almost vault over the supporting leg. However, walking in itself is not perfect. Walking is a fluid motion where a lot of muscles have to make a lot of movements. Some of them are bound to make mistakes. If you are not blind-folded you could easily fix these errors and stay straight. However, once you are blind-folded fixing these mistakes doesn’t happen quite as often and you will veer off path. Even if you don’t have a blindfold on, if there is no clear visual landmark for you to work off of, i.e. the sun, you will veer of path just as easily.
If possible my experiment will be done indoors to avoid then sun piercing through the blindfold and acting as a visual landmark. If this is not possible then I will attempt to do my research on a cloudy day, or account for the sun in the results. The definition of walking noted above will be the same I will be using in my tests, a slow controlled movement over a surface.
In my experiment I will be using sounds in an attempt to replace the visual aid that is needed to stay straight. However, I will only be using distinct sounds, such as an alarm beeping. The sounds I will use will be as clear and distinct as possible in an attempt to set it apart from any background or white noise. I will do multiple trials on each participant with the noise coming from a different area to see how it influences their walking. With about half of the participants I will tell them where the noise is coming from, i.e. straight ahead, to their left/right, or behind them, and see how their walking path is influenced.
F. Lacquaniti, R. Grasso, M. Zago. Motor Patterns in Walking. August 1999. 7 March 2012.
Krulwich, Robert. A Mystery: Why Can’t we Walk Straight. 7 march 2012.
The free dictionary. 7 march 2012.
The Free Dictionary. 7 March 2012.